In particular, the researchers believe that changes in milk consumption may not necessarily be connected to changes in soda and flavored fruit drinks.

“We found that children's milk consumption did decrease between 5th and 8th grade, but the changes weren't related to changes in their consumption of sweetened beverages," explained lead investigator Reena Oza-Frank, an epidemiologist with the Center for Perinatal Research of The Research Institute at Nationwide Children's Hospital and the Department of Pediatrics at the Ohio State University, in a prepared statement. "In addition, regardless of how much sweetened beverages children consumed, milk and 100% fruit juice were complements in children's diets. Children increased or decreased their intake of both in tandem."

In the study, the team of investigators looked at the beverage consumption of 7,445 students who participated in the Early Childhood Longitudinal Study Kindergarten Class of 1998-1999 (ECLS-K). The ECLS-K, a nationally representative study of children between kindergarten to eighth grade, included a food consumption questionnaire that polled students on the frequency of consumption and amount of consumption of milk, 100% fruit juice, and sweetened beverages.

The researchers then compared the data to determine changes in consumption over a period of time. They factored in demographic traits, socioeconomic status, and things such as if the student attended public or private school education, if the child participated in a free or reduced-price lunch program, and if the child regularly ate breakfast or lunch. Lastly, they included nutrition measurements that looked at consumption of fruits, vegetables, and fast food.

Based on the results, children appeared to consume fewer calories of beverages between the fifth and eighth grade. With that, milk consumption dropped while the consumption of 100% fruit juice rose. As well, milk consumption declined even more so for children who sipped sweetened beverages as opposed to those who drank none. The findings showed that there was a sharper drop in milk consumption for children who had daily consumption of sweetened beverages; these students tended to have an average of two fewer glasses of milk when they were enrolled in the eighth grade as opposed to when they were in fifth grade. Furthermore, males and whites drank the most sweetened beverages. Those who drank sugary drinks on a daily basis were often enrolled in public school, consumed breakfast and school lunch on a regular basis, and participated in a free or reduced-price school lunch program.

On the other hand, the researchers found that changes in children´s consumption of milk and juice weren´t related to changes of consumption of soda. As a result, they concluded that sweetened beverages did not replace other kinds of drinks. Over the three-year period, children who upped their milk consumption also upped their juice consumption.

“Analysis of multiple subpopulations indicates that milk and juice consumption increased or decreased in tandem for most children," noted Oza-Frank in the statement.

The scientists recommend that total beverage intake should be tracked as children who drink more of one high caloric beverage will tend to pick up in their consumption of other high caloric drinks.

"It's important for [food and nutrition practitioners] to help children and families understand that caloric beverages, even those that are generally healthful, contribute to children's total calorie intake and must be moderated as a part of a healthy diet," concluded Oza-Frank in the statement.